Toss-bombing aid for aircraft



United States 3,003,398 TOSS-BOMIEING AID FUR AIRCRAFT John 0. Lalli, Los Angeles, Calif., assigner to Sperry Rand Corporation, a corporation of Delaware Filed Nov. 30, 1955, Ser. No. 549,918 5 Claims. (Cl. 89-1.5)

This invention relates to improvements in toss-bombing aids for aircraft. More particularly, it concerns a novel arrangement for facilitating the accurate determination of that unique point in an aircrafts pull-out from a substantially straight dive toward a target Where the Y trajectory of a given free-falling bomb or missile released from the craft will intersect the target.

'Ihetactic of releasing a bomb from an aircraft during its pull-out from a dive toward the target for which the bomb is intended is generally termed toss-bombing. The correct release point in a toss-bombing maneuver arentY 5 maneuver against the target.

The present invention is directed toward providing al data needed for such determination. Prior to the entry for a given bomb configuration depends principally uponVY Y the horizontal and vertical velocities of the craft relative to the surrounding air mass and upon the horizontal and vertical distances between the craft andthe target.

of the` diving craft into the pull-out portion of the maneuver, a changeover is made from the crafts distance measuring equipment to the crafts velocity measuring equipment, thevelocity data from which is than inte-- grated with respect to time and subtracted from .the directly-obtained range data that prevails at the instant of Y the changeover so that the required range data is supplied without interruption throughout the maneuver. .Y

An object of the present invention is to provide an improved toss-bombing aid wherein the vertical and Ihori- Toalesser extent, dependence is also had on such factors,

for example, as relative motion between and target and the surrounding air mass, meteorological conditions, and height to target above sea level. However, these lesser factors merely provide corrections to the basic release point determination, and are of no direct interest in regard to the present invention.

Aircraft of the single-place lighter-bomber type are generally employed for toss-bombing operations. As longas such a craft is on the dive portion of its tossbombing maneuver against a given target, the target is within direct view of the pilot-bombardier. A line of sight to the target during craft dive is thus readily established by optics, radar, or `other suitable means. With a knowledge of the direction of this line with respect to the local .vertical and of the slant range to the target or the valtitude of the craft, the horizontal and vertical distances between the craft and the target may be computed.

However, when the craft enters the pull-out portion of its toss-bombing maneuver, the line of sight to the target zontal distances from Iaircraft to target may be continuously and accurately determined throughout the dive and pull-out portions of a toss-bombing maneuver of the craft against the target.

Another object of the present invention is .the provision of a toss-bombing aid wherein time-integrated velocity data may be substituted for directly obtained range data before the latter is lost due to craft pull-out from its dive toward target in order to provide a conitinuous supply of range data notwithstanding such loss.

may be lost due to obstruction of the pilots view of the i target by the nose assembly of the craft, or due, where radar is employed, to the crafts radar axis being in fixed general alignment with the longitudinal axis of the craft, hence pointed away from the target during craft pull-out from the dive portion of the toss-bombing maneuver. Therefore, if the computation of the horizontal and verticaldistances between the craft and the target depends upon the maintenance of the line of sight to the target, .the computation will cease with pull-out land it becomes necessary to estimate or dead-reckon these distances thereafter.

Toss-bombing l aids for aircraft in the past have :attempted to solve the dead-reckoning problem in a number of different Ways, most of which impose special restrictions on the parameters of the pull-out portion of the maneuver, such as a requirement for constant radial path acceleration, extremely difficult for the pilotbombardier to conform to, especially under stress of combat. In such prior arrangements, the release point has elapsed time since pull-out, and any departure from the requisite programmed maneuver has necessarily resulted in serious bombing error. Furthermore, it has generally been necessary to clamp or store a range or altitude value on a shaft or signal transducer at the instant of initiation of 'the equipment, leading to undue stress, inaccuracy, mld PQSSble malfunction. Y

Another object is to provide 'a toss-bombing aid according to the second object above wherein the transition..

from directly obtained range data to range data obtained by. velocity integration is achieved in a smooth uninterrupted manner.

Another object is the provision of a toss-bombing aid which functions to determine the proper bomb-release point in a crafts toss-bombing maneuver irrespective of p the flight parameters of the craft during the pull-out por- 40 tion of the maneuver.

binations and arrangements thereof described below and illustrated in the accompanying drawings, in which FIG. l is a diagram of the ilight path of an aircraft engaged in a toss-bombing maneuver, including the crafts y velocity and range-to-target components; and

FIG. 2 is a schematic block diagram of `an embodiment of the present invention.

The toss-bombing maneuver yas customarily executed comprises two distinct portions as illustrated in FIG. 1."

These are Van initial dive, designated by the flight path segment AB, in a substantially straight line directly to- During the pull-out, a unique point C will be passed at which a bomb, when released from the aircraft 4 will strike the target.

As earlier stated, the release point depends principally 0 upon the horizontal and vertical velocities (V11 and Vv) ofthe craft relative to the surrounding air mass and upon the horizontal and vertical Vdistances (a' and h) between j been determined-bjzaesiri'J erf1nenti-measdireiangleeieyr:craftrairdrtarget 'fne'frequisiteorizonta VandY 'vertical' velocity information maybe continuously obtained, for example, by measuring true air speed and thereafterfrei solving such measurement into the quadrature componentsV thereof for whatever the ight path angle Gnof' the craft relative to the horizontal may be during the-*- of pullout, resulting in discontinuities in the functioning dive tand pull-outportions of the toss-bombing maneuver. f1 On the other hand, the requisite horizontal and vertical .,distance informatiomin theusual case, maybe obtanedf Y Patented Oct. l0, 19617Y ward a target 3, and a pull-out, designated by the curved segment BCD in a vertical plane containing the target; i

mnn-x H by direct measurement and resolution during the dive portiorr, only, of the maneuver.

By referring now to FIG. 2, it will be seen how the present invention may provide a continuous ow of data concerning the' horizontal and Vertical distancesbetween craftf and target throughout both portions of the tossbombi'ng maneuver.

A signal proportional to the slant range hom the craft to: thetargetl is obtained during craft dive from a distance measuring equipment, such as a radar range device 5, andi is supplied'via a lead 6 to a resolver 7. Besides the range signal, resolver 7' receives another signal input, proportional'v to the flight path angle G of the craft, suppliedvia leads 8, 9 from an apparatus 10 which may include a vertical gyroscope and angle of attack sensor. In`- response toits range and llight path angle inputs, resolverv T provides a'signal proportional to the horizontal range component d on a resolver output lead 11, and a'signal' proportional to the vertical range component h on-a resolver output lead 12.

Anormally-closed switch 13 connects lead y11i. to a lead 14 which is connected to an input lead 15 of an amplifier 16'. The output of amplifier 16 is fed via a lead 17 to a motor 18 for energizing the same to drive a pair of signal generators 19, 20. Generator 19 is of the tachometer type forV providing a signal on its output lead 21 proportional to the rate at which it is driven by motor 18, while generator 2t? is of the position displacement type for providing a signal on its output lead 22 proportional to the amount it is driven by motor 18. The displacement signal' on lead 22 is fed via a lead 23 and a normallyclosed' switch 24 to a second input lead 25 of amplifier 16; inf negative feedback fashion, so that motor 18 is normally driven an amount proportional to d, whereby the displacement signal on lead 22 is likewise proportional toad.'

In order to maintain the displacement signal on lead` lead/212 proportional to the difference between the value` of. d then prevailing and the time integral of the horizontal component of true air speed.

A signal proportional to the true air speed of the craft is continuously obtained from a true air speedY meter 28, and is supplied via a lead 29 to a resolver 30 similar to resolver 7; Besides the air speed signal, resolver 30 receives another signal input, proportional to the ight path angle G-of the craft, supplied via-leads 8, 31 from apparatus In Vresponse to its air speed and flight path` angle inputs, resolver 30 provides a signal on a resolver output lead 32 proportional to the horizontal component V1,A of the true air speed, and a signal proportionalto the vertical true air speed component Vv on a resolver output lead 33.

The closing of normally-open switch 27 connects the lead 32 to input lead 15 of amplifier 16, while the closing of normally-open switch 26 connects the tachometer output lead. 2'1 to feedback lead 25 of amplier 16. Hence, byY opening the switches 13 and 24 while closing the switches 26 and 27, motor 18 is driven at a speed proportional to Vn. The sense with which the Vh signal is fed' to amplier 16 is such that motor 18 is driven in the same direction as for a decreasing d signal on lead 14. ByV this arrangement, therefore, the displacement signal that` prevails on lead 22 when the switches are simultaneously actuated from their respective normal conditions is thereafter diminished steadily by an amount proportionalE to the time integral of Vh, the latter being proportionall tothe horizontal distance traveled bythe craft sincezsuch switch. actuation. The operating transition-of 4 r Y the servomechanism, that is formed by amplifier 16, motor 18Vv and' generators 19 and 20, from a signal repeating mode to a signal integrating mode, occurs smoothly and without producing any discontinuity in the horizontal range signal output on lead 22;

Switches 13', 24, 26, 27' are ganged together and preferably' form a part of the electromagnetic relayV 34:60htrolled by a single manually-operated switch 35m-series with a power supply 36 and the winding of the relay. To close the normally-open switches 26, 27 and open the normally-closed switchesv 13, 24 as required during craft dive and before pull-out, the pilot-bombardier. has merely to close theY switch 35, hereafter termed the change-over switch.

An arrangement identical to that just described forproviding a continuous horizontal range signal is employed for providing a continuous vertical range. signal. However, instead of the arrangement being responsive in the alternative to the d signal output of resolver 7 and the V1, signal output of resolver 30, depending on the condition of pull-out switch 35, it is alternatively responsive` to the h'signal output of resolver 7 and the VV signal output Y ofresolver 30; To this end, an amplifier 40, a motor^41,` and a' pair of generators 42, 43 are provided which respectively'correspond to the amplilier 16, motor 18, and generator pair 19, 20. Two normally-closed switches.' 44, 45 correspond respectively to switches v13, 24V and two Vnormally-open switches 46, 47 correspond respectively to switches 27, 26. The vertical component switches are ganged together with the horizontal component switches to complete the relay 34 so that all eight of the switches are controlled by pull-out switch 35.

Thus, when the change-over switch 3S is open, the servomechanism formed by amplifier 40, motor 41, and generators 42 and 43 is in its signal repeating mode of operation, so that the lz signal output of resolver 7, fed via switch 44 to ampliiier 40, is repeated on the outputY lead' 48of displacement generator 43. And when the changeover switch is closed in preparation for pull-out, the servomechanism is placed in its signal integrating mode of-v operation, so that the Vv signal output of resolver 30,l

fed via. switch 46 to ampliier 40, is integrated with respect tov time and subtracted from the h signal output on lead 48 prevailing at the instant of changeover switch closure, whereby to maintain the output of generator 43 proportional to the horizontal range component.

Having provided for a continuous supply of range component data, the remaining portion of the tossbombing aid depicted in FIG. 2 is concerned with theuse of this data together with the velocity component data available for determining the proper release point inl the pull-out portion of the crafts toss-bombingA In this connection, the arrangement to be- 50 to a dividing network 51 which also receives the d signal onv lead 22 via a lead 52. 'Ihe signal output of network 51 is proportional to d Vn or the horizontal time of flight tf1, for a vacuum trajectory, and is fed via a lead 53 to a ballistic correction device 54 which applies a correction to the In, signalv 'according to the usual factors including air temperature andl density, bomb conguration and wind. The ,Vv

signal on lead 33 is fedY via a led 55 to aV position servo-A mechanism 56, and the h signal onlead 48' isfed viavacuum trajectory, the timeof fall tf, cfa bomb through the distance h when released with the'vertical velocity Vv rs where g is the acceleration of gravity. Thus, cam 59 is designed, in view of Equation l, to impart a motion to its follower 60 proportional to tf., in response to the mechanical inputs of h and Vv. 'Ihe follower motion is transduced by a signal generator 61 into an electrical signal proportional to rfv which is fed via a lead 62 to a ballistic correction device 63 for applying a correction to the tf, signal according to the usual factors as performed by device 54.

The corrected tn, and t1, signals are fed via leads 64 and 65, respectively, to a signal comparison device 66. When input signals to device 66 are such as to represent equal values of horizontal time of ight and vertical time of night, device 66 generates a signal on its output lead 67 which is connected to a signal-responsive bomb release mechanism so as to release the bomb.

Since many changes could be made in the above construction and many -apparently widely diierent embodiments of this invention could be made without departing from the scope thereof, itis intended that all matter contained in the above description or shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense.

What is claimed is:

1. In a toss-bombing system for aircraft, means providing a signal in accordance with the horizontal component of the slant range from the craft to the target during the dive portion of the maneuver, means providing a signal in accordance with the horizontal cornponent of the velocity of the craft during the pull-out portion of the maneuver, a servomechanism operable in a signal repeating mode and a signal integrating mode to produce a continuous signal in accordance with the horizontal component of slant range from the craft to the target, and change-over means operable to connect said horizontal slant range component signal means and said servomechanism in the signal repeating mode during the dive portion of the maneuver and to connect said horizontal velocity component signal means and said servomechanism in the signal integrating mode during the pull-out portion of the maneuver.

2. In a toss-bombing system for aircraft, means providing a signal in accordance with the vertical component of the slant range from the craft to a target during the dive portion of the maneuver, means providing a signal in accordance with the vertical component of the velocity of the craft during the pull-out portion of the maneuver, a servomechanism operable in a signal repeating mode and a signal integrating mode to produce a continuous signal in accordance with the vertical component of the slant range from the craft to the target, and changeover means operable to connect said vertical slant range component signal means and said servomechanism in the signal repeating mode during the dive portion of the maneuver and to connect said vertical velocity component signal means and said servomechanism in the signal integrating mode during the pull-out portion of the maneuver.

3. In a toss-bombing system for aircraft, means providing signals in accordance With the vertical and horizontal components of the slant range from the craft to a target during the dive portion of the maneuver, means providing signals in accordance with the vertical and horizontal components' of the velocity of the craft during the pu11-out portion of the maneuver, a servomechanism operable in a signal repeating mode during the. dive portion of the maneuver and a signal integrating mode dur- 3 ing the pull-out portion of the maneuver to producel a continuous signal Ain accordance with the vertical corn-- ponent of the slant range from the craft to the target, a servomechanism operable in` a signal repeating vinode during the dive portion of the maneuver and a signal integrating mode during the Apull-out portion of the maneuver to produce a continuous signal in accordance with the horizontal component of the slant range from the craft to the target, and change-over means operable Y to connect the vertical component signal of said slant range signal means to said vertical component servomechanism in the signal repeating mode; to connect the horizontal component signal of said slant range signal means to said horizontal component servomechanism in the signal repeating mode; to connect the vertical component signal of said velocity signal means to said vertical component servomechanism in the signal integrating mode; and to connect the horizontal component signal of said velocity signal means to said horizontal component servomechanism in the signal integrating mode.

4. A system for controlling the release of bombs from an aircraft in a toss-bombing maneuver with a dive portion and a pull-out portion, means for producing a signal in accordance with the vertical component of the velocity of the craft in the maneuver, means for producing a signal in accordance with the horizontal component of the velocity of the craft in the maneuver, means for producing a primary signal in accordance with the vertical component of the slant range from the craft to a target during the dive portion of the maneuver, means for producing a primary signal in accordance with the horizontal component of the slant range from the craft to the target during the dive portion of the maneuver, integrating means operable during the pull-out portion of the maneuver for providing an alternative vertical slant range component signal responsive to the vertical component craft velocity signal means, integrating means operable during the pull-out portion of the maneuver for providing an alternative horizontal slant range component signal responsive to the horizontal component craft velocity signal means, change-over means operable during the dive portion of the maneuver prior to the pull-out portion thereof for switching the system from the primary vertical component slant range means and the primary horizontal component slant range means to the alternative vertical component slant range means and the alternative horizontal component slant range means, means for continuously combining the velocity and slant range signals of said respective vertical component signal means effective in the respective portions of the maneuver to provide an output, means for continuously combining the velocity and slant range signals of said respective horizontal component signal means eifective in the respective portions of the maneuver to provide `an output, and means for comparing the outputs of said respective combining means to control the release of the bomb during the pull-out portion of the maneuver.

5. A system for controlling the release of bombs from an aircraft in a toss-bombing maneuver with a dive portion and a pull-out portion, means for producing signals in accordance with the vertical and horizontal components of the velocity of the craft in the maneuver, means for producing primary signals in accordance with the vertical and horizontal components of the slant range from the craft to a target during the dive portion of the Y pull-oui porong thereofl for svi/itching Y'dieV systeml from'V che-s131711: range means l to lshe `alternaaive slnt' range; means; n1ea11e7-fo'r4 continuously combining the verticali component velolsityYV and slant range signals` of saidfrespc'otive sgnalnneans= eeetive; in the respective portonslof the maneuver to provide an output, meansY yforconnuously combiningv the horizontal ednlponentl velocity and-i slant range signalsl of 'said respective'signal means-eieetve inthe'respective portions ofthe maneuvertolprov-de am` output, and` means for comparing the out'i puts of said2v respective Ycombining means to control the release ofofhe -bomb duringi -thepull-out portion of the maneuver.

References (iited`- inithe le" Vor.' flamentV ,Y

m1113513,Y STATES@T PATENTS? rY Y Morton- Sept, 10, 1957 Y 

